In communication systems, whether they conform to GSM, CDMA, or other technology standards, the communications between the base stations and the mobile terminals typically include one or more traffic channels for communicating data signals and one or more control channels for exchanging control signals. For some signal control channels, for example, a pilot channel of CDMA systems, the control signals have to be broadcasted omni-directionally to cover the whole or sectored cell. On the other hand, it is desirable to steer narrow beams formed for communicating through traffic channels with specified mobile equipment without interfering with other mobile equipment nearby. The beam formed pattern is directed to particular users, and it has a narrow beam width.
Logically, this can be done by two approaches: the first approach is to generate the beamforming pattern via one set of antennas and generate the omni pattern via another set of antennas. The second approach is to use a single set of antennas but the omni pattern needs to be synthesized with the beamforming pattern. However, the first approach will add the costs associated with the omni pattern generation. The physical arrangement of two antenna sets also adds some difficulties to the first approach. There are discussions about beam forming and omni broadcast synthesis issues. The difficulties of synthesizing omni-broadcast patterns with beam forming means remain as challenges awaiting newer and better engineering solutions.
Therefore, there exists a need to provide an improved approach that allows antenna arrays to provide both beam forming and omni patterns simultaneously without the need of either an additional antenna set for omni pattern or omni pattern synthesis.